Psoriasis is a chronic inflammatory skin disease that is seen in less than 1% of infants by 1 year of age and 2% of infants by age 2. Infantile psoriasis resembles adult psoriasis with discrete oval, erythematous plaques with white scale often involving the trunk, extremities, and face. There is usually less white scale on the plaques of infants as compared to adults. Lesions may be pruritic. The disease process results in hyperproliferation of epidermal cells causing thickened, often scaly skin. Lesions usually develop slowly but may have a sudden onset. Psoriasis in infancy typically involves the diaper area and face. Nail findings of pitting, onycholysis, oil spots, and subungual hyperkeratosis are present in 10% of affected infants.
L40.0 – Psoriasis vulgaris
402330006 – Onset of psoriasis in infancy (<1 year)
Differential Diagnosis & Pitfalls
- Seborrheic dermatitis – Favors intertriginous areas and has a greasy rather than dry, flaky scale.
- Atopic dermatitis – Usually spares the diaper area and more commonly affects the shins and forearms.
- Cutaneous candidiasis – Responds to antifungal therapy, has satellite pustules, and pseudohyphae using potassium hydroxide (KOH) preparation.
- Acrodermatitis enteropathica – Initially vesicular or bullous; periorificial and acral preference; often associated with diarrhea, alopecia, and failure to thrive.
- Irritant diaper dermatitis – Spares skin folds and limited to diaper area.